<html>
<head>
<script>
function Run() {
// iframe in head.
document.head.appendChild(document.createElement('iframe'));
// iframe in a child of head.
var d = document.createElement('div');
document.head.appendChild(d);
d.appendChild(document.createElement('iframe'));
// iframe in body.
document.body.appendChild(document.createElement('iframe'));
}
</script>
</head>
<body onload="Run()">
</body>
</html>